The proliferation of compact personal computing devices, such as Personal Digital Assistants (PDA's), mobile phones, and miniature notebook computers has led to a great deal of variation with regard to keyboard design and layout, as well as data input functions. For handheld devices that feature full text input capability, most manufacturers have tried to facilitate the traditional QWERTY layout for their keypads in order to maintain a correspondence with familiar computer and typewriter keyboards.
Although their small size facilitates convenience and portability, present portable computing devices typically present significant disadvantages associated with text-based data input. Many new designs provide individual keys for different letters and numerals. However, fitting all of the keys necessary to accommodate the letters, numerals, punctuation, and function buttons on a space limited roughly to the size of a person's hand, requires that keys be made very small. This greatly hinders the convenience and usability of such keyboards, as it is nearly impossible to type quickly and accurately with such small buttons. As an alternative, some designs feature double or triple keystroke combinations to form certain characters. This allows for some of the keys to be eliminated, and the remaining keys to be enlarged, to the extent that space permits. However, this design is also inconvenient and somewhat clumsy due to the fact that new keystroke techniques must be learned, and double or triple tapping can further limit typing speeds. Furthermore, the reduction in the number of keys often does not allow a significant increase in the size of the remaining keys to a size that allows easy data entry. It is therefore desirable to provide a portable device keyboard system that provides the ergonomic efficiency of a traditional QWERTY keyboard, but that features near full-size keys for easy data entry.
Present trends in PDA design are moving toward greater integration of features within individual devices. Advanced PDA devices and mobile phones feature various integrated functions, such as cell phone capability, two-way radio communication, word processing, data storage, electronic mail (e-mail), web browsing, and other such functions, all in a single hand-held device. Such highly integrated devices have some appeal among the segment of users who value having access to a full range of mobile functionality, yet insist on carrying a minimum number of different devices. However, there are many users who do not mind carrying separate devices, and in fact may prefer to carry a cell phone as well as a separate PDA-type device. Because of the space constraints discussed above, highly integrated, “all-in-one” devices are often complex, hard to use, and non-optimized for specific functions. When used as a mobile phone, typical PDA devices are too large. Conversely, present cell phone form-factors are too small to be useful as full function PDA devices. For this reason, it is also often desirable to carry separate mobile phone and PDA devices. This allows each device to be used in the manner in which its design is optimized.
Because manufacturers have typically been more concerned with integrating functions in a single device, little development has been devoted to integrating the functionality of mobile phones and PDA devices as separate but cooperative devices. However, these devices share common elements, such as display screens, keypads, speakers, and microphones, that can be used together to form a single networked device. Such cooperative networking can result in a compound device that provides a higher degree of usability and convenience than the two devices provide separately. In this manner, the two devices can be virtually integrated into a single unitary device, to provide a greater ease of use than a single highly integrated device. Therefore, it is also desirable to provide a system of networking a mobile telephone type device and a PDA type device to produce a portable networked device that combines the features of both devices while allowing both to be used independently from one another.